1. Field of the Invention
The invention relates to an information carrier for writing and/or reading information blocks in/from a track intended for recording and arranged in a helical or concentric pattern of windings, the track being determined by a servo pattern on the information carrier, the servo pattern comprising synchronization elements and a modulation, in which modulation position-information is coded.
The invention further relates to a reading/writing device comprising reading/writing means for reading and/or writing information blocks from/in an information carrier track intended for recording, the track being arranged in a helical or concentric pattern of windings, and determined by a servo pattern on the information carrier. The servo pattern comprises synchronization elements and a is modulated with coded position-information is coded. The device has a read/write head for scanning the track and a system control for controlling the scanning in dependence on the synchronization elements.
The invention further relates to a reading device comprising reading means for reading information blocks from a track on an information carrier, the track being arranged in a helical or concentric pattern of windings and the track being determined by a servo pattern on the information carrier, the servo pattern comprising synchronization elements, the device comprising a read head for scanning the track and a system control for controlling the scanning.
2. Description of the Related Art
An information carrier and a device of the type defined in the opening paragraph for reading and/or writing information thereon are known from U.S. Pat. No. 4,901,300, issue Feb. 13, 1990, assigned to Philips. The information is coded to form an information signal which may be subdivided into addressable information blocks as on a CD-ROM. The information carrier has a pregroove for producing tracking servo signals, the radial position of which pregroove periodically varies in a so-termed wobble. The device comprises a read/write head for scanning the track. During the scanning, this wobble causes a modulation of the tracking servo signals. This modulation comprises code modulation synchronization elements and position-information which position-information denotes the absolute length of the track from the starting point. The information blocks are recorded on the information carrier at a desired position that corresponds to their address, the position of the read/write head in the track being derived from the position-information. The writing of the information blocks is synchronized with the synchronization symbols.
A problem for such a system is that the read/write head may wanders off the track and cause information in an adjacent track to be destroyed as a result of a defect or a shock during writing.